Lec 3: Prokaryotic structure and function Flashcards
Bacteria plasmid
Circular
Supercoiled dsDNA
Replicate independently of host chromosome
Carry genes not essential to host but useful in certain environments
Binary fission
1 bacterial cell undergoes repeated rounds of division -> single colony composed of identical cells
Shape of prokaryotes
Coccoid (spherical)
Rod/bacillus (cylindrical)
Spirillium (spiral)
Spirochete (helical)
Square
Arrangement of prokaryotes
Chains
Packets: symmetrical
Clusters: not symmetrical
Bacteria structure
Nucleoid
Cytoplasm
Plasma membrane
Cell wall
Bacteria nucleoid
dsDNA
Encodes genes essential for life
Bacteria cytoplasm
Cytoplasmic matrix: between plasma membrane and nucleoid
Ribosomes
Cytoplasm: organic inclusion bodies
Glycogen: energy reserve
Poly-beta-hydroxybutyrate: energy reserve
Cyanophycin: nitrogen reserve
Carboxysomes: carbon dioxide fixation
Gas vacuole: flotation -> buoyancy in aquatic environments
Cytoplasm inorganic inclusion bodies
Polyphosphate granules
Sulfur granules
Magnetosomes: used for movement. Bounded by membrane
Internal membrane of bacteria
Thylakoid membranes: photosynthesis. Lined with phycobilisomes containing pigments
Bacteria plasma membrane
Amphipathic phospholipids -> bilayer
Fluid mosaic model
Proteins
Selectively permeable. 1st step in transport of proteins
Bacteria cell wall
Maintain shape
Provide protection from: osmotic shock, action of anti-bacterial agents
Gram +ve
Purple
Bacillus, staphylococcus, Streptococcus
Thick layer of peptidoglycan
Teichoic acids
Gram -ve
Reddish pink
Escherichia, neisseria, pseudomonas
Thin layer of peptidoglycan
Periplasm
Outer membrane
Endotoxin(lipopolysaccharide)
Porin proteins
